What better way to see Barcelona at night than through the lens of time-lapse footage? This beautiful footage from the city was put together by Pau Garcia Laita. The lights of Barcelona against the night sky look surreal in this video and the music perfectly accompanies scenes of swirling motion from the cars’ headlights, the transformation of a periwinkle sky into a royal-blue sky into a midnight-blue sky and finally into a black sky, and the specific vibrancy this city exudes in the face of modernity, history and inspiring landscape. I’ve seen and posted a lot of time-lapse videos on Gadling, but this is one of my favorites so far.

What’s a feast day? Certain Christian traditions, notably Roman Catholic, keep track of which liturgies are given when by way of something called the General Roman Calendar, or Universal Calendar of Saints. Around 60 percent of the days of the Gregorian calendar year are associated with one or more saints, martyrs or holy figures. Even some relics have feast days. The feast day for St. Peter’s chair is on February 22. St. John the Baptist’s feast day falls on June 24.

Interestingly, St. Christopher, the patron saint of travelers, lost his feast day back in 1969. A lot of people think St. Christopher was “desanctified,” or lost his sainthood, but in fact he was just stripped of his feast day because there’s no proof he actually existed.

Also interestingly, the patron saint of travelers is also the patron saint of bachelors and bookbinders, among other things.

You were saying about St. John the Baptist… Right.

So why June 24 of all days? That’s when John the Baptist is said to have been born. But more than that, Christianity has a long tradition of co-opting pagan rituals into Christian holidays. It’s a good way to gain converts. Pagan celebrations generally aligned with the turning of the seasons – equinoxes and solstices. And so Christians have major holidays around these dates: Easter near the vernal equinox, Christmas near the winter solstice and Michaelmas, which celebrates Lucifer being cast out from heaven, near the autumnal equinox.That June 24 is close to the summer solstice is certainly not a coincidence. Even if the summer solstice used to be celebrated on a different date (which it was when we used the Julian calendar), the church would have had a significant feast day to coincide with such a major celebration in the northern hemisphere.

Is that why it’s particularly popular in northern Europe? Bingo, mysterious person. St. John’s Day is celebrated all over the world, but the biggest celebrations occur in traditionally Christian nations well above the equator. In strongly Christian countries like Ecuador, where there is little change in sunrise and sunset throughout the year, it’s not such a big deal. But in Tallinn, Estonia, the sun sets at about 10:45 p.m. on the summer solstice and 3:30 p.m. on the winter solstice. St. John’s Day is just an extension of the reverence these places have for the summer solstice.

But isn’t it celebrated in Brazil? Yes, and other places where colonial powers instilled their traditions. Joao Fernandes, an early Portuguese explorer, was particularly devoted to the holiday and took John the Baptist as the patron saint of his exploits at Pernambuco, which is where St. John’s day is celebrated most in Brazil today. Fernandes had canons fire salutes around the camp all day long in celebration. This was in no small part because he shared the same name with the saint.

John the Baptist is also the patron saint of French Canada. And Turin, Italy and Porto, Portugal and numerous other places as well. That’s why Quebec celebrates June 24 as its national day.

abdallahh, Flickr

Is it celebrated the same everywhere? Not quite, though most celebrations share one thing in common: fire. If there’s one thing everyone does on St. John’s Eve, it’s get rid of their old furniture and spare kindling in a giant bonfire. Or if you’re in Shetland, Scotland, where wood is in short supply, your excess heather and peat.

The city of Poznan in Poland had a unique take on the fire tradition in 2012, when they released 8,000 Chinese lanterns into the sky on St. John’s Night, setting a world record in the process.

Bonfires are more typical and are found everywhere, from prominent mountain peaks to valleys and plains. If you’re a traditional fisherman from Brittany, France…

I’m not. Well, if you were, you’d even light a fire on top of your ship’s mainmast to celebrate with your fishing fleet. Curiously, Breton fisherman are said to have a fear of tailors, another group that John the Baptist patronizes.

Elsewhere, the celebrations have unique local flavor. In Scandinavia, figures of witches are added to the flames because, as on Halloween, demons and evil spirits are said to be able to roam freely this day. Up until the 1700s, the French would incinerate cats by the sackful and chase a flaming cat through the streets, evil incarnate as they were (the cats, not the French… ostensibly).

Latvians eat a special cheese flavored with caraway seeds. Ukrainians eat eggs, dumplings and liquor for dinner. Ukrainians will also symbolically wash themselves with the morning dew after watching the sun rise, as do the Lithuanians.

Dace Kiršpile, Flickr

The Irish and others will set a wagon wheel on fire and roll it down a hill to symbolize the sun’s decline. With any luck, there’s nothing flammable at the bottom. Many cultures will dress in traditional costumes. Russians douse each other with water in one of the few actual nods to John the Baptist. The Swedes, celebrating their Midsommar festival a few days before St. John’s Day, raise a giant pole that is supposed to imbue the earth with fertile soil.

Sounds phallic. Indeed. In fact, most rites and rituals surrounding the summer solstice have to do with fertility. Many of the cultures celebrating St. John’s incorporate dancing and singing erotic songs into the celebrations, much to the consternation of the Church, I expect. It’s said to be a good time to predict who will be your future spouse, as well.

No need. Well, another common activity is jumping through the flames. It’s said to cleanse and purify the soul. Or you could wear a garland of flowers.

Not really for me, either. Can I just see some photos? Sure. Check out a slideshow of St. John’s Day (and Night) celebrations from around the world below.

Want to be an explorer? Want to see places nobody has ever seen? You have three options: become an astronaut, become a deep-sea diver or become a caver.

The first isn’t going to happen for a man my age and the second is expensive, so it’s a good thing I live in one of the best regions in the world to do the third. Cantabria in northern Spain has a large amount of karst, a type of stone that often has caves.

One of them is Luna Llena (“Full Moon”), which has yet to be fully mapped. In my fourth caving expedition in Spain I was part of a team that went to look for new passages. I was thrilled. Seeing unexplored parts of the subterranean world was one of the reasons I got into caving. I didn’t think the payoff would come so quickly.

Luna Llena is at the bottom of an abandoned galena mine from the 1920s. The miners were blasting with dynamite one day and opened up a hole into an unknown cave. It’s been regularly explored ever since but there are still many blank spots on its map.

The mineshaft slopes sharply down into the bedrock. Walking along an old narrow-gauge track past ore wagons and rusted equipment, we soon arrived at the cave. There were four of us, two experienced cavers who would be doing the bulk of the mapping, myself, and another relative newbie named Nacho. I quickly discovered that this would be the toughest cave I’d faced in any country.Karst often forms narrow, deep passageways, the product of underground streams cutting away the stone. These passageways can be five, ten, a hundred meters high. There’s no real floor, just a gradual narrowing until you reach water at the bottom. The only way to traverse these is a technique called “chimneying,” in which you straddle the passage with a hand and a foot on each wall. If it gets a bit too wide you press your feet against one wall and your back against the other. You keep tied into a rope running along the wall so you don’t risk falling into the abyss.

This workout led to a payoff – a low chamber filled with soda straws, thin little tubes hanging on the ceiling that eventually form stalactites. We had to crawl on our hands and knees below these beautiful formations for several minutes before getting to a place where we could stand up.

A little more exploring brought us to a long, high passageway. Several small tunnels led away from it, several blanks on the map. We picked one and crawled inside.

This is where it really got interesting. We were off the map in a place nobody had ever seen. Sadly I didn’t have my camera. My Instamatic died the previous week and I wasn’t going to risk my SLR in these conditions. Nacho brought his, but since he was behind me the only shots he got of me were of the bottom of my boots. The tunnel was too small for anything else.

It was almost too small for us to move. Crawling along in a military low crawl, the tops of our helmets scraping against the roof, we came to a spot where the tunnel pinched.

One of the more experienced cavers turned and looked at me.

“You sure you want to do this?” she asked. “Stop and think about it.”

“Of course I want to do it.”

“You’re not claustrophobic?” she asked.

“If I was claustrophobic I would have started freaking out ten meters ago.”

She shrugged and wormed her way into the tunnel. I gave her time to get through and then went in myself. The only way to enter this part was to have both arms stretched out ahead of me. Even then my shoulders barely made it through. I edged my way forward with my forearms and feet, the tunnel pressing in on all sides. Breathing became difficult. There wasn’t enough room to inhale fully, but I was exerting myself and needed the air. Every move was an effort. I wondered if I would make it through. I didn’t panic, though. My only worry was that Nacho was going to have to grab my boots and haul me out.

Any lingering doubt that I have claustrophobia was snuffed out when my headlamp suffered the same fate. An outcropping in the rock hit the power button and the tiny space I was in plunged into darkness.

It didn’t matter. I hadn’t been seeing anything but the rock an inch in front of my nose anyway. Continuing by feel, I made it to a slightly wider part of the tunnel where I could bend my arm and switch on my light. Ahead of me was an even tinier tunnel turning at an acute angle. The caver ahead of me called back.

“Come on through. It’s like a second birth!”

The birth canal I actually had to push off with my legs and force my body through. I exhaled, crushing my chest as flat as it could go. My head and arms emerged in a little cyst in which sat two of our team. Another push and my shoulders made it. A final effort to get the stomach through, swearing all the way to give up beer. I felt the cave walls pressing against my stomach and the small of my back and then I let out a tremendous fart. The cave literally squeezed it out of me.

Poor Nacho. He was right behind me and had nowhere to run. I hoped he didn’t asphyxiate. He was my ride.

We all gathered in the cyst, Nacho looking a bit green around the gills. During all this time our more experienced leaders had been mapping the passageway. Now we got a chance. This was basic mapping, with a compass, tape measure, and clinometer. It was meticulous work in cramped conditions, yet highly rewarding. All my life I’ve studied maps, especially old ones with their tempting blank spots marked Terra Incognita. And now here I was in Subterra Incognita.

I studied every fissure and formation, hoping to find another passage branching away form the one we were in. None were wide enough to push through. The tunnel soon turned back and rejoined one of the main mapped passageways. We’d mapped maybe a couple of hundred meters. In the annals of discovery this is a very minor footnote. I didn’t care. It made all the scrapes and bruises worth it.

So if you want to be an explorer, consider caving. It’s not as hard as you think. I’m 43 years old and only moderately fit. Chances are you can do what I do. If you live in the U.S., the best way to get into it is to join the National Speleological Society. With more than 10,000 members and about 250 local chapters (called “grottoes”), there’s probably a group near you.

Traveling to Spain or Latin America this summer and want to say more than “Donde esta el bano?” (though, that’s an important one to know)? Lonely Planet has just launched a new online foreign language program, Fluent Road, partnering with Spanish language program Fluenz. The focus is on Spanish for now, but you can choose from dialects from Argentina, “neutral” Latin America, Mexico, or Spain.

Fluent Road is designed for travelers to get the basics before a trip: Spanish for transportation, finding accommodation, ordering food, etc. It’s also a good stepping-stone to a more intensive learning program, and travelers could easily work up to a Fluenz course after completing Fluent Road. What differentiates this from other language learning like Rosetta Stone or Pimsleur is a dissection of the language, showing you how Spanish works and providing explanations, not just rote immersion. Fluenz founder and avid traveler Sonia Gil guides you through obstacles, pronunciation, and practice speaking, writing and reading as a native speaker and “language geek.”

As with all online learning, you can go at your own pace; there are 30 video lessons that can be completed in one to six months. Other useful features include the ability to record yourself to compare pronunciation a native Speaker, and customizable digital flash cards to help practice. You can also contact the teacher and program designer via Twitter.

Take a free 12-hour trial now, subscriptions start from $9 for a month to $30 for six months of access, at www.fluentroad.com.

Capturing a stunning combination of architecture and weather, Flickr user Mike Rowe took this black and white photo at the palace of Charles V, contained within the Alhambra in Grenada, Spain.

Commissioned as a royal residence close to the Alhambra palace, the 16th-century building is a square, two-level structure done in the Renaissance style. It’s also home to two museums: the Museo de la Alhambra and the Museo de Bellas Artes. With this photo perspective, you certainly get a feel for the grandiose scope the building.